Stencil printing machine



Oct. 29, 1935. J. s. WHEELWRIGHT 2,019,375

STENCIL PRINTING MACHiNE Fil ed Dec. 18, 1934 7 Sheets-Sheet 1 D m (D DU h m Om J. S. WHEELWRIGHT STENCIL PRINTING MACHINE Filed Dec. 18, 1954 '7 Sheets-Sheet 2 Oct. 29, 1935.

Oct. 29, 1935- J. s. WHEELWRIGHT STENCIL PRINTING MACHINE Filed. Dec. 18, 1934 7 Sheets-Sheet 4 mK mp 1935- J. s. WHEELWRIGHT 7 STENCIL PRINTING MACHINE Filed Dec. 18, 1934 7 Sheets-Sheet 5 Fig.5.

1935- J. 5. WHEELWRIGHT STENCIL PRINTING MACHINE Filed Dec. 18, 1934 7 Sheets-Sheet 6 Oct. 29, 1935. J. s. WHEELWRIGHT 2,019,375

STENCIL PRINTING MACHINE Filed Dec. 18, 1954 7 sheet -sh eet Patented Oct. 29, 1935 UNITED STATES PATENT OFFICE STENCIL PRINTING MACHINE John Sylvester Wheelwright, Tonbridge,

England Application December 18, 1934, Serial No. 758,121 In Great Britain December 23, 1933 a pattern or stencil through which ink or colour may be applied on to sheet material such as textile material, paper, sheet metal or the like.

According to the present invention a stencil surface in the form of an endless band (or a number of such stencil surfaces operating in sequence) is moved along with and in contact with the surface of the material to receive the printed impression during the printing operation.

One form of machine for printing textile material, paper, sheet metal or the like by this method comprises means to support the surface to be printed and one or a number of endless stencil bands guided over two or more guide drums and displaced over said drums either independently or by frictional contact due to their relative displacement with the surface to be printed, ink or the like material being passed to the inner surface of the stencil bands between said drums.

The invention will now be described with reference to the accompanying drawings which show, more or less diagrammatically, a machine comprising a number of stencils each for printing differing coloured parts of a design which is to be printed repeatedly on a web of fabric or other material.

In the drawings:-

Figures 1 and la are a sectional elevation of a machine for printing material on a conveyor, the two end stencils only being shown.

Figures 2 and 2a are a plan thereof.

Figure 3 is a section on the line 3-3 of Figure 4.

Figure 4 is a side elevation of one stencil unit and associated parts.

Figure 5 shows the means for maintaining the stencil taut laterally.

Figure 6 is a section on the line 6-6 of Fig ure 5.

Figure '7 is a detail view showing a squeegee roller and associated doctor blade.

Figure 8 is a detail view of a device for adjusting a stencil circumferentially, and

Figure 9 is a perspective view showing a stencil unit for printing material laid on a stationary printing table.

Like reference numerals indicate like parts throughout.

The machine shown in Figures 1 to 6 comprises a flat bed 10 over which travels in contact therewith an endless rubber conveyor belt II having on its underside a longitudinal rib l2 which is serrated to allow of its bending. This rib runs in a slot l3 in the bed 10. Thus the conveyor belt is constrained to travel in a straight 5 path over the bed. Ifdesired, a number of transversely arranged rollers mounted close together side by side may be provided for supporting the upper stretch of the conveyor belt instead of the bed ID, or the latter may be made in 10 sections with a roller at each end and between each two sections. The belt ll passes around drums l4, 15 arranged one at each end of the bed [0 and rotatably mounted in bearings on the main frame l6. be provided for supporting the lower stretch of the conveyor belt. Motion may be imparted to the conveyor belt by any convenient means. The means shown on the drawings for this purpose is a belt drive I! connecting a transverse driving 20 shaft I8 with the shaft of the drum 15.

The material to be printed is a web of fabric l9 .which is temporarily united to a backing web of waterproof material 20; a roll 2| of this duplex material being provided at one end of the machine. The web of duplex material is led from the roll 2| over a guide roller 22 and is laidon the conveyor belt I l thesurface of which is moistened by means of a roller 23 which dips into a. trough of water 24. The web on the conveyor belt passes beneath stencils 25 for printing the fabric, and after leaving the bed l0 the web of fabric and the backing web are separated. The 'fabric l9 passes around a heated drying drum 26 and thence around guide rollers 21, 28 s to the required destination, while the backing web is led around guide rollers-29, 30 and is wound on a spindle 3|.

Each stencil 25 is in' the form of a movable endless belt which passes around three rollers 32, 33, 34 disposed above the conveyor belt at the corners of a triangle. The rollers 32, 33 are rotatably mounted a fixed distance apart at one end in fixed brackets 35 and at the other end in brackets 36 which are hinged on .a horizontal hinge pin 31 5 for the purpose hereinafter described, see especially Figures 3 and 4. These rollers constitute holding-down members and are spaced apart longitudinally of the conveyor for holding the stencil in contact with the fabric to be printed. The 50 spindle of the roller 34, which is located at the apex of the triangle, is mounted in brackets 38 which are adjustable vertically to maintain the stencil in tension. Each bracket 38 is connected to a block 39 which can be adjusted along vertical 5} Rollers (not shown) may also 15 guides 40 by means of a screw 4| arranged to be operated by bevel gearing 42 from a common shaft 43 provided with a hand wheel 44 whereby it can be rotated. In the construction shown on the drawings, the stencils 25 are frictionally driven from the conveyor belt I I, but it is to be understood that if desired the stencils may be positively driven and the conveyor belt be frictionally driven therefrom, or alternatively a driving connection comprising interengaging elements on the conveyor belt and on the stencils may be provided.

Each edge of each stencil is attached to a thin strip 46 of metal or other stiffening material which is provided with inwardly projecting pins 46 spaced apart at equal distances longitudinally of the stencil for engagement with a number of similarly spaced recesses 41 in the stencil rollers 32, 33, 34. Thus the stencils are maintained taut in a lateral direction.

The printing colour for each stencil is contained in a receptacle 48 whichis detachably mounted on the fixed bracket 35. This receptacle communicates with a delivery pipe 49 which is disposed across the stencil slightly above the lower stretch thereof and is perforated along its length so as to feed the colour on to the inner face of the lower stretch of the stencil between the rollers 32, 33. The colour is confined between the edges of the stencil by means of two guides 50 carried by the brackets 35, 36 and disposed one near each edge of the stencil. At the rear of the pipe 49 in the direction of feed of the fabric to be printed, a squeegee blade 5| is provided for pressing the colour through the stencil. This squeegee blade is mounted on a can'ier 52 which is vertically adjustable by means of screws 53 in guides 54 on the brackets 35, 36 thus permitting pressure of the squeegee blade on the stencil to be adjusted at will.

Instead of the squeegee blade 5|, 9. squeegee roller 55 of any suitable material may be pro vided for pressing the colour through the stencil, see Figure 7. The spindle of this roller may be mounted similarly to the squeegee blade 5| to permit the pressure exerted by the roller on the stencil to be adjusted. Behind the roller 55 in the direction of travel of the fabric to be printed, a doctor blade 56 is provided for cleaning the stencil. This doctor blade is arranged in proximity to the squeegee roller 55 and connects the colour guides 50. Associated with the doctor blade 56 is a shield 51 for the squeegee roller, said shield being mounted in the brackets 35, 36 and so arranged that colour scraped by the doctor blade 56 from the screen will be carried, due to the rotation of the squeegee roller, to the pool of colour 58 which is deposited on the stencil in front of the squeegee roller. 11'' it should be found necessary to drive the squeegee roller at a speed appropriate to the surface speed of the stencil, this may be done in any convenient way, for example by means of gearing or by providing a pinion on each end of the squeegee roller to be engaged by the pins 46 on the stencil.

It is desirable that all the stencils shall move at the same surface speed and to ensure this the stencils are interconnected by means of a skew gear wheel 59 on one end of the spindle of the roller 33 of each stencil. The skew gear wheel 59 engages a skew gear 60 on a shaft 6| extending longitudinally of the stencils and carried by brackets 62 on the printing unit.

The spindles of the rollers 32, 33 project at each end beyond the rollers and these projecting ends of said spindles are mounted in the brackets 35, 36. The bracket 35 is belted to a longitudinal channel bar 63 and the bracket 36 is carried by the hinge pin 31 which is mounted in lugs 64 on a longitudinal channel bar 65, there being a pair I of channel bars 63, 65 associated with each stencil. The bracket 36 is held in its operative position by means of a belt and wing nut 66.

The two channel bars 63, 65 are connected by cross-members 61 at each end to form a rigid 10 frame unit. On this unit the brackets 35, 36 are mounted, and these brackets carry the bearings for the two lower screen rollers 32, 33 and the guides 54 for the carrier 52 for the squeegee blade or roller together with mountings for the shield 15 51 if provided and the colour guides 50. The colour delivery pipe 49 is connected to the colour receptacle 48 which is mounted on a projection 68 from the bracket 35 so that both pipe and receptacle may be removed as a unit. After removing the colour pipe and receptacle, by swinging down the hinged bracket 36, the colour guides 50, the squeegee blade or the squeegee roller and its shield, the stencil rollers and the stencil may be removed in order.

Associated with the stencils is a device for raising them from the printing bed It). This device comprises beneath each stencil two transversely arranged shafts H which are rotatably mounted in bearings on the main frame I 6. Between the sides of the main frame these shafts each carry an arm I2, and said arms are all interconnected by a longitudinally extending link 13. One of the shafts 'II is provided with a handle 14 whereby it can be turned. Each of the shafts H also car- 86 ries two cams 15, one at each side of the machine, each cam engaging a roller 16 carried by a bracket 11 secured to the underside of the corresponding longitudinal channel bar 63 or 65. Each bracket 11 is also provided with a guideway 18 in which a 0 uide block 18 on the main frame is received to permit vertical sliding movement of the bracket 1'! thereon. Thus by turning the handle 14 to rotate the cams 15, the stencils can be raised from or lowered on to the printing bed. The guides 45 40 are also supported on the longitudinal channel bars 63, 65 and therefore partake of the aforesaid raising and lowering movements.

It will be appreciated that if instead of the single link 13, separate links are provided con- 60 meeting together the arms 12 associated with each stencil with a handle 14 on one of the pair of shafts beneath each stencil that the stencils can be raised or lowered independently of one another.

From the foregoing description it will be seen that each stencil and its associated parts above the bed III are all supported on the longitudinal channel bars 63, 65 which can be lifted clear of the guide blocks 19 on the main frame I 6. This 0 permits the stencil and said associated parts to be removed bodily from the machine as a unit should that be necessary for any purpose.

In order to provide a fine adjustment for adjusting any one of the stencils circumferentially for the purpose hereinbefore explained, the de vice shown in Figure 8 may be employed. In this device each skew gear 60 is splined to the shaft 6| and held between the side arms of a U-shaped 70 housing 80 which is movable longitudinally of the shaft 6| by means of a thumbscrew 8| rotatably mounted in a lug 82 on the bracket 35. By rotating the thumbscrew 8|, the skew gear 60 can be moved longitudinally so as to turn the skew gear 7 wheel 59 and thus effect the required adjustment of the stencil.

In Figure 9 one stencil unit for printing on material l9 laid on a stationary printing table 83 is shown. This unit comprises a rectangular frame 84 in which the spindles of the rollers 32 83 are rotatably mounted. The colour receptacle 48 and its delivery pipe 49, the roller 34 and the squeegee 5| are also mounted on the frame 84, the roller 34 and the squeegee 5| being adjustable vertically by screw adjusting devices 85, 86 respectively for t1! purpose hereinbefore explained. Along one side of the printing table 88 a toothed rack 81 is provided and is engaged by a pinion 88 on the spindle of the roller 33. A pinion 88 is provided on each of the stencil units required for printing a multi-coloured design. This enables accurate register of the various parts of a design printed by the separate stencils to be obtained by providing a registration mark on each of the stencils to register with a corresponding mark on the printing table. Guide wheels 88 running on rails 98 are provided to keep the stencil unit aligned to the table. Any convenient means may be adopted to afford 1: 1 ratio drive from the rack 81 to the surface of the printing stencil 25. In the construction shown in Figure 9 the pinion 88 which is mounted on the spindle of the roller 88 fulfills this function.

The stencil unit shown in Figure 9 may be manually propelled by means of a rod 9| on the frame 84 or may be power driven, for example by means of a small electric motor driving a pinion in engagement with the rack 81.

I declare that what I claim is:-

1. A stencil printing machine comprising a number of endless stencil bands, means to support 5 material to be printed, a pair of rollers supporting each stencil band, the axes of which rollers lie in a plane parallel to the surface of the material to be printed, a frame supporting the axes of said rollers and means to displace said frame normal- 10 1:7 to the printing surface.

2. A stencil printing machine comprising a number of endless stencil bands, means to support material to be printed, a pair of rollers supporting each stencil band, the axes of which 15 rollers lie in a plane parallel to the surface of the material to be printed, a frame supporting the axes of said rollers, means to displace said frame normally to the printing surface, gearing interconnecting a roller engaging each stencil band 20 and means to displace a roller of any one band angularly relatively to a roller of any other band.

3. A stencil printing machine comprising a number of endless stencil bands, a table adapted to support material to be printed, pairs of rollers 25 supporting each stencil band, the axes of which lie in a plane parallel to the printing surface, a shaft normal to the axes of all rollers, gear connections between a roller on each band and said shaft and means to alter the angular disposition of the gearing between said roller and shaft.

JOHN SYLVES'I'ER WHEELWRIGHT. 

